144 PROCEEDINGS OF THE AMERICAN ACADEMY 



Action of Bromine and Water. 



Since pyromucic acid itself is readily attacked by aqueous bromine, 

 and converted, according to the conditions of the reaction, into fumaric 

 aldehyd or mucobromic acid, it seemed to us of interest to study the 

 behavior of the S-monobrompyromucic acid under similar conditions. 

 We have found that the products formed vary greatly according to 

 the conditions chosen, but in every case they prove to contain but 

 four carbon atoms. 



The acid was suspended in about thirty times its weight of cold 

 water, and the vapor of bromine slowly led in by means of a current 

 of air. Two molecules of bromine were found necessary to complete 

 the reaction. The strongly acid solution, when extracted repeatedly 

 with ether, gave an acid sparingly soluble in cold water, more readily 

 in hot, which, when recrystallized from hot water, proved to be free 

 from bromine. The behavior of this acid on heating showed it to be 

 fumaric acid. Its identity was further established by an analysis of 

 the silver salt. 



0.5462 grm. of the salt gave 0.6194 grm. AgBr. 



Calculated for Ag2C4H„04. Found. 



Ag 65.46 ' " 65.13 



Beside the fumaric acid could be isolated minute quantities of two 

 acids which contained bromine, and which from their physical proper- 

 ties appeared to be dibromsuccinic and isodibromsuccinic acids. These 

 acids were formed in much larger quantity when the bromine was 

 rapidly added ; considerably more than two molecules of bromine were 

 required to complete the reaction, and at the same time a crystalline 

 substance insoluble in water was then formed. The aqueous solution 

 was filtered from this insoluble substance and extracted with ether. 

 The ethereal extract upon evaporation left a white crystalline residue 

 which contained but little fumaric acid, and proved to consist mainly 

 of about equal quantities of two acids, which could be separated by 

 repeated recrystallization from water. The more soluble acid could 

 be obtained by slow evaporation in well-formed rhombic plates which 

 melted at 165°, and which on analysis proved to contain the percent- 

 age of bromine required by isodibromsuccinic acid. 



I. 0.2434 grm. of substance gave 3344 grm. AgBr. 

 11. 0.2427 grm. of substance gave 0.3305 grm. AgBr. 



Calculated for Found. 



CiHiBr.O^. I. n. 



Br 57.97 58.44 57.94 



